1. Field of the Invention
This invention relates generally to the field of cellular materials used as window coverings.
2. Description of the Prior Art
Cellular window coverings are well known in the art. These products have a series of interconnected cells usually made from fabric material. Typically, these products are made by folding and gluing sheets or strips of material to create a cellular structure or by connecting a series of webs between two parallel sheets. One advantage of using two parallel sheets is that the front of the shade can be a different material than the back of the shade.
One type of cellular window covering is made from two flat sheets of material which are pleated and then glued face to face at the apex of the folds to form the cells. Some examples of this type of cellular construction are described in U.S. Pat. No. 4,861,404 to Neff and U.S. Pat. Nos. 4,673,600, 4,677,012 and 4,685,986 to Anderson.
Another type of cellular window covering is constructed by folding over the edges of flat sheets of material and gluing the free edges to form a cell, or multi-cellular structure, and then stacking and gluing the cells on top of each other to form the cellular window covering. The cells can be cut to the width of the window in which it will be installed. Some examples of this type of cellular construction are described in U.S. Pat. Nos. 5,701,940 and 5,692,550, to Ford et al., U.S. Pat. Nos. 5,691,031 and 5,690,778 to Swiszcz et al., U.S. Pat. Nos. 4,603,072 and 4,450,027 to Colson, and U.S. Pat. No. 4,732,630 to Schnebly.
Another type of cellular window covering is produced by joining together multiple flat sheets of material along alternating glue lines between each flat sheet. Several sheets of material can be joined this way to form multiple honeycomb shaped rows of cells or a row of cells can be cut at a bond line if a single row of cells is desired. The cells can then be cut to the width of the window in which it will be installed. Some examples of this type of cellular construction are described in U.S. Pat. Nos. 4,388,354 and 4,288,485 to Suominen and U.S. Pat. No. 5,228,936 to Goodhue.
Another method of producing a cellular window covering is disclosed in U.S. Pat. No. 5,193,601, to Corey, et al., in which a multi-cellular collapsible window covering is made from a continuous sheet of flexible material. The sheet of flexible material is pleated in a manner to create permanent folds in the material at regular intervals in alternating directions so that the material collapses easily into a compact stack. Bonds between adjacent folds in the pleated material are formed either by welding or adhesive or other bonding agents along lines parallel to and equidistant from both sides of the pleats.
Judkins in U.S. Pat. No. 5,339,882, discloses a window covering having a series of slats connected between two spaced apart sheets of material. The slats are substantially perpendicular to the sheets of material and connected to the sheets by flexible strands. Related U.S. Pat. Nos. 6,068,039 and 6,033,504 teach that the spaced apart sheets may be translucent materials and the webs or slats placed on the webs may be opaque. The slats are substantially parallel to the first and second sheets of material when the window covering is in a closed position.
In U.S. Pat. No. 5,753,338 relic et al. disclose a honeycomb material for window coverings in which the front face, rear face and slats are interwoven simultaneously. This process uses an improved warp knitting technique in which a front mesh and a rear mesh are provided and warp threads are woven through them. The two meshes are maintained parallel to one another. At selected intervals slats are woven between the two meshes to form a honeycomb structure. This window covering has not been commercialized.
The use of flexible strands for the web portion of cellular shades provides the advantage that lift cords can be easily threaded through the cells. Yet, all of the cellular materials that contain webs formed of flexible strands or threads have a front sheet and a back sheet that extend the full length of the shade. Prior to the present invention there were no cellular structures in which individual cells were made of distinct pieces of fabric connected by strands.
We provide a cellular material in which a plurality of interconnected cells each have a front section and a rear section. These sections are configured to form a V-shape or C-shape and are positioned so that the free edges are opposite one another. A section of swirled strands is connected between one free edge of the front section and one free edge of the rear section. If desired a second section of swirled strands can be connected between the second edge of the front section and the second edge of the rear section to form a closed cell. The cells are connected to one another by a pair of glue beads adjacent or on top of the section of swirled strands. In one embodiment the glue beads are positioned such that one glue bead bonds the first edge of a front section of one cell to the second edge of the front section of an adjacent cell and the second glue bead bonds the first edge of the rear section of that one cell to the second edge of the rear section of the adjacent cell. The front section and the rear section may employ woven, non-woven, knit fabrics and/or film substrates. The same fabric or different fabrics can be used for the front section and the rear section.
The front section and the rear section can be made of transparent or translucent fabrics and a slat of opaque material can be placed within each cell resting on a section of swirled strands. When the front sections of the cells are moved relative to the rear section of the cells, the opaque slats are tilled from a horizontal position toward a vertical position blocking the passage of light through the cellular structure.
The front section and rear section can be of equal size to create a symmetrical cell or they may be of different sizes to create a D-shaped or other non-symmetrical cell. Furthermore, the front section and rear section may have permanent pleats or soft folds that will fall out giving the structure a Roman shade-like appearance.
The cellular structure can be made on machinery that fully automates the production process. In this machinery two strips of fabric from separate rolls are folded and aligned edge to edge with a cord space between the aligned edges. Then swirled strands are applied between them using air jets to carefully control their position.
Other objects and advantages of the invention will become apparent from a description of certain present preferred embodiments thereof shown in the drawings.